1. Technical Field
The present invention relates to leadframe processing and, more particularly, to a leadframe metallization technique useful in molded packaging arrangements.
2. Description of the Prior Art
In many current integrated electronic and/or optoelectronic circuit arrangements, one or more semiconductor components are positioned on a leadframe and encased in a package so as to form, for example, a single in-line package (SIP) or dual in-line package (DIP) structure. The package may be, in some cases, molded from a plastic to completely encase the circuit components. Typically, electrical signals are transmitted to/from such a molded package to an associated circuit board by a plurality of leads which comprise the package leadframe structure. However, in some cases, the need arises to provide a direct electrical contact between the molded package and another device without passing the connection through the circuit board (e.g., in situations where the signal degradation associated with the circuit board is unacceptable).
A problem with the direct wirebond connection is that an essentially clean wirebond contact on the molded package is required to provide the necessary electrical and mechanical integrity. However, inherent in the molding operation is the residue and/or bleed of molding compound, a resin, which will adhere to the exposed wirebond surface. Conventional cleaning agents, which may be capable of removing the resin from the exposed gold wirebond pad sites, are not acceptable alternatives since they have been found to attack the molded plastic package and/or gold wirebond contact, as well as require a one-at-a-time cleaning process (costly as compared to a "batch" cleaning system).
A need remains, therefore, for a method of improving the electrical quality of wirebond attachments to leadframes utilized in molded packaging arrangements.